Casing scraper



April 24, 1962 M. B. CONRAD CASING SCRAPER Filed Feb. l, 1960 2 Sheets-Sheet 1 an f,

Maf v 5M-@M April 24, 1962 Filed Feb. l, 1960 M. B. CONRAD CASING SCRAPER .WWII

2 Sheets-Sheet 2 IN V EN TOR.

United tates Patent 3,031,016 CASING SCRAPER Martin B. Conrad, 9326 S. Rives Ave., Downey, Calif. Filed Feb. 1, 1960, Sel'. No. 6,048 12 Claims. (Cl. 166-173) This invention relates to well tools and is particularly adapted for use in a device for scraping the inner surface of a casing in place in a well. Casing scrapers are used for various purposes, such as to remove cement sheaths, to remove burrs resulting from perforations of the casing, to true-up out of round casing, and to smooth and round the interior of casing which has become damaged adjacent a liner by passage of well tools therethrough.

It is the principal object of this invention to provide an improved formV of casing scraper which will perform these functions in a superior fashion and which is characterized by a short over-all length and which is very sturdy and capable of withstanding severe service. Another object is to provide a casing scraper device of this type having adequate clearance for fluid within the casing and which may be used on a string of pipe or suspended from a wire line. Another object is to provide a casing scraper device for use on a string of pipe which is capable of ltransmitting high torque loads from the body of the tool to the scraper blades. Another object is to provide a device of this type having a minimum number of parts .and employing no threaded fastenings such as bolts or cap screws.

Another object is to provide a novel form for mounting of scraper blades on a central tubular body. Other and more detailed objects and advantages will appear hereinafter.

In theY drawings:

FIGURE 1 is a side elevation showing a preferred embodiment of this invention positioned within a Well casing, the casing being shown in cross section.

FIGURE 2 is a longitudinal sectional elevation.

FIGURE 3 is a sectional elevation showing a part of the body with only the lower set of scraper blades assembled in position.

FIGURE 4 is a perspective view of one of the scraper blades.

FIGURE 5 is a transverse sectional view taken substantially on the lines 5 5 as shown in FIGURE 2.

FIGURE 6 is a transverse sectional view taken substantially on the lines 6-6 as shown in FIGURE 3, with two additional scraper blades in the upper set shown in operative position.

FIGURE 7 is a framentary view showing -a modified form of scraper blade surface.

Referring to the drawings, the tubular body generally designated 10 may be threadedly connected at its upper end to a sub 11 and this sub may be carried on the lower end of a pipe string 12. or secured to the lower end of a wire line (not shown).

The body has a central axial opening 13 extending therethrough and aligned with the opening 14 within the sub 11 and Within the pipe string. The tubular body is provided with an even number of longitudinal ribs 15 which extend from the upper shoulder 16 to the lower shoulder 17. rI'hese ribs 15 are equally spaced circumerentially and define between them the same number of longitudinal channels 18. In the particular form ofthe invention shown in the drawings, there are six ribs 15 and six channels 18 but a greater or lesser number may be employed, if desired. Each of the channels 18 has parallel side walls 19.

Two sets of scraper blades are mounted on the tubular body 10 in circumferentially staggered position. The upper set generally designated 20 contains a plurality of blades 21 and the lower set 22 contains a plurality of similar blades 21. Each set of scraper blades includes one-half as many blades 21 as there are ribs 15 on the body 10. Thus, for six ribs 15 there are three scraper blades 21 in each set. All of the blades are preferably identical. Each scraper blade 21 is provided with an arcuate outer face 23 having horizontal teeth 24 and vertical teeth 24a both shaped for scraping engagement with the inside surface 25 of the well casing 26. The particular shape of the teeth may take any one of a number of forms. FIGURE 7 shows a tooth form which is particularly suited for either rotary or longitudinal cutting movement.

Each blade 21 is provided with an inwardly extending retainer tlange 27 on each side edge thereof and each retainer flange has an inwardly directed tongue 2,8 on its projecting end. Two tongues on each blade 21 extend into nonadjacent channels 18, and the adjacent tongues 28 on adjacent blades 21 extend into the same channel. Spring means .are provided for moving each blade 21 outward with respect to the body 1d, and as shown in the drawings, this spring means includes a plurality of coil springs 29 each mounted in .an individual pocket 30 provided in the vback face centrally of each blade 21 (see FIGURE 4). Each of these coil springs 29 extends into a channel 18 which is positioned between the channels engaged by the tongues 28 on that particular scraper blade 21.

Each rib 15 is provided with a pair of shoulders 31 and 31a. One shoulder on each rib is engaged by abutments 32 and 33 provided on the retainer flange 27 of each scraper blade 21. These shoulders and abutments provide means for transmitting torque from the body 10 to the scraper blades 21. It will be noted that the clearance distance A across two adjacent ribs between shoulders 30 and 31 is greater than the clearance distance B between the inner extremities of the tongues 28 (See FIG- URE. 5). Accordingly, the tongue 28 engages the side walls 19 of the channels 18 to limit outward movement of the scraper blades 21 under action of the coil springs 29, before entry of the tool into the casing 26.

Novel means are provided for installing the scraper blades 21 is position on the tubular body 10. As best shown in FIGURES 3 and 6, each rib 15 is provided with axially spaced grooves 34 and 35. These grooves are positioned near the upper shoulder 16. Each groove extends from lthe extreme outer surface of 4the rib l5 and intersects one of the side walls 19 of the adjacent channels 18. Only one side of each rib is provided with grooves 34 and 35 and hence only one Wall 19 on each channel is intersected by one of these grooves.

As best shown in FIGURE 4, one of the retainer flanges 27 of each scraper blade 21 is cut away at a central location to provide a slot 36. All of the blades 21 are iden- -tical and the slot 36 is on the same side of each blade. The length of the slot 36 is slightly greater than the longitudinal distance between the grooves 34 and 35.

The blades 21 together with their coil springs 29 are installed on the body 10 before installation of the keeper ring 37. This ring is normally held in place by the sub 11 and it encompasses the body 10 in the region containing the upper grooves 34 in the ribs 15. Before the ring 37 is installed, and as shown in FIGURE 4, each scraper blade 21 may be applied laterally to the body 10 with the slot 36 in the blade in registry with the space between the rib grooves 34 and 35. This position of the blade 21 is shown in phantom lines in FIGURE 3. The blade is installed by swinging it between the phantom line positions shown in FIGURE 6.

The three scraper blades of the lower set 22 are rst installed one by one and are then moved longitudinally along the ribs 15 to their operating positions adjacent the abutment 38. This abutment 38 is provided by the split ring 39 which is fixed on the body l'10 as by welding 40. The three scraper blades 21 of the upper set 20 are then installed circumferentially staggered position with respect to the lower set 22. Thus, the retainer tongues 28 of the blades 21 in the upper set 20 are mounted in channels engaged by the coil spring 29 of the blades 21 of the lower set 22. The staggered positions of the blades in the two sets 20 and 22 assure full circle contact with the internal surface 25 of the casing 26. The rib grooves 34 and 35 provide enough clearance to permit swinging of the individual scraper blades 21 into position on the body 10. Subsequent longitudinal movement of the scraper blades downward away from the shoulder 16 moves them out of registry with the grooves 34 and 35 and hence, the interengagement of the tongues 28 and side walls 19 of the channels 18 prevents disassembly. The ring 37 is then installed and held in place by the sub 11, and the two sets 20 and 22 of scraper blades 21 are confined between the abutment 38 on the split ring 39 and the abutment 41 on the keeper ring 37. The split ring 39 and the keeper ring 37 thus serve as retainer means to limit longitudinal movement of the blades 21 relative to the body 10.

In the construction illustrated, it is not possible through inadvertence to assemble the scraper blades 21 in an inverted position, because the position of the rib grooves 34 and 35 and the retainer flange slots 36 permits installation in only one position.

In the modification of FIGURE 7, the outer surface of each blade 21a may be provided with a series of helically staggered pockets 50, Each pocket has adjacent teeth defining a vertical cutting edge 51 and a horizontal cutting edge 52. In other respects the blades 21a are the same as those previously described.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details set forth herein but my invention is of the full scope of the appended claims.

I claim:

1. In a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferentially, said ribs defining a plurality of longitudinal channels therebetween, a circumferential series of scraper blades mounted on the body, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer flange on each side edge thereof, an inwardly directed tongue on each retainer flange, the tongues on each blade extending into nonadjacent channels, adjacent tongues on adjacent blades extending into the same channel, means including retainer means on said body limiting longitudinal movement of said blades relative to said body, and spring means on each blade extending into one of said channels between those engaged by said tongues and acting to move the blade outward with respect to said body.

2. In a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferentially, said ribs defining a plurality of longitudinal channels therebetween, a circumferential series of scraper blades mounted on the body, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer flange on each side edge thereof, an inwardly directed tongue on each retainer flange, the tongues on each blade extending into nonadjacent channels, means including retainer means on said body limiting longitudinal moveent of said blades relative to said body, spring means on each blade extending into one of said channels between those engaged by said tongues and acting to move the blade outward with Yrespect to said body, the clearance distance between said tongues on each blade being less than the clearance distance over two adjacent ribs.

3. In. a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferentially, said ribs defining a plurality of longitudinal channels therebetween, each of the channels having parallel side walls, a circumferential series of scraper blades mounted on the body, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer flange on each side edge thereof, an inwardly directed tongue on each retainer flange, the tongues on each blade extending into nonadjacent channels, adjacent tongues on adjacent blades extending into the same channel and engageable with opposite side walls thereof, means including retainer means on said body limiting longitudinal movement of said blades relative to said body, and spring means on each blade extending into one of said channels between Ithose engaged by said tongues and acting to move the blade outward with respect to said body.

4. In a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferen-tially, said ribs defining a plurality of longitudinal channels therebetween, each of the channels having parallel side walls, a circumferential series of scraper blades mounted on the body, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer flange on each side edge thereof, a shoulder on each rib, an abutment on each retainer ange engaged by a rib shoulder, an inwardly directed tongue on each retainer flange, the tongues on each blade extending into nonadjacent channels, adjacent tongues on adjacent blades extending into the same channel, means including retainer means on said body limiting longitudinal movement of said blades relative to said body, and spring means on each blade engaging one of said channels between those engaged by said tongues and acting to move the blade outward with respect -to said body, the clearance distance between the tongues on each blade being less than the clearance distance over the rib shoulders adjacent the tongues to limit outward movement of the blade.

5. yIn a casing scraper, the combination of: a body having an even number of longitudinal ribs equally spaced circumferentially, said ribs defining the same number of longitudinal channels therebetween, a circumferential series of scraper blades mounted on the body, the series having one-half as many blades as the number of ribs on the body, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer flange on each side edge thereof, an inwardly directed tongue on each retainer flange, the tongues on each blade extending into nonadjacent channels, `adjacent tongues on adjacent blades extending into the same channel, means including retainer means on said body limiting longitudinal movement of said blades relative to said body, and spring means on each blade extending into one of said channels between those engaged by said tongues and acting to move the blade outward with respect to said body.

6. In a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferentially, said ribs defining a plurality of longitudinal channels therebetween, first and second sets of scraper blades mounted on the body, the first set being circumferentially staggered with respect to the second set, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer flange on each side edge thereof, said retainer flanges on each blade having tongues extending into nonadjacent channels, retainer means on said bodyv limiting longitudinal movement of said blades relative to said body, and spring means on each blade extending into one of said channels between those engaged by tongues on that blade and acting to move the blade outward with respect to said body, the spring means on the first set of blades engaging channels receiving blade tongues on the second set of blades.

7. In a casing scraper, the combination of a body having an even number of longitudinal ribs equally spaced circumferentially, said ribs defining the same number of longitudinal channels therebetween, first and second sets of scraper blades mounted on the body, each set having one-half as many blades as the number of ribs on the body, the rst set being circumferentially staggered with respect to the second set, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer ange on each side edge thereof, said retainer flanges on each blade having tongues extending into nonadjacent channels, retainer means on said body limiting longitudinal movement of said blades relative to said body, spring means on each blade extending into one of said channels between those engaged by the tongues on that blade and acting to move the blade outward with respect to said body, the clearance distance between the tongues on each blade being less than the clearance distance over two radjacent ribs to prevent disassembly of the blades from the body prior to entry into a casing, the spring means on the iirst set of blades engaging channels receiving blade tongues on the second set of blades.

8. In a casing scraper, the combination of: a body having six longitudinal ribs equally spaced circumferentially, said ribs deiining six channels therebetween, rst and second sets of scraper blades mounted on the body, each set having three blades, the iirst set being circumferentially staggered with respect to the second set, the blades in each set being identical, each blade having an arcuate outer face prepared for scraping engagement with the inside surface of a casing, each blade having a retainer iiange on each side edge thereof, said retainer flanges on each blade having tongues extending into nonadjacent channels, retainer means on said body limiting longitudinal movement of said blades relative to said body, spring means on each blade extending into one of said channels between those engaged by the tongues on that blade and acting to move the blade outward with respect to said body, the clearance distance between the tongues on each blade being less than the clearance distance over two adjacent ribs to prevent disassembly of the blades from the body prior to entry into a casing, the spring means on the irst set of blades engaging channels receiving blade tongues on the second set of blades.

9. In a casing scraper, the combination of: a tubular body having a plurality of longitudinal ribs equally spaced circumferentially, said ribs defining a plurality of longitudinal channels therebetween, each of the channels having parallel side Walls, first and second sets of scraper blades mounted on the tubular body, the rst set being circumferentially staggered with respect to the second set, the blades in each set being identical, each blade having an arcuate outer face provided with teeth for engaging the inside surface of a casing, each blade having a retainer flange on each side edge thereof, each retainer flange having a radially extending tongue, said tongues extending into nonadjacent channels, retainer means on said body limiting longitudinal movement of said blades relative to said body, springs on each blade extending itno one of said channels between those engaged by the tongues on that blade and acting to move the blade outward with respect to said tubular body, the clearance distance between said tongues on each blade being less than the clearance distance over two adjacent ribs to prevent disassembly of the blades from the tubular body prior to entry into a casing, and the springs on the rst set of blades engaging channels receiving blade tongues on the second set of blades.

v10. In a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferentially, the ribs defining a plurality of longitudinal channels therebetween, each of the ribs having a pair of longitudinally spaced grooves near one end thereof intersecting a side wall of an adjacent channel, a set of scraper blades mounted on said body, each blade having an arcuate outer face provided with teeth for engaging the inside surface of a casing, each blade having a retainer ange on each side edge thereof, each retainer flange having a tongue extending into one of said side channels, a central portion of one retainer flange on each blade having a slot, said grooves on said ribs and said slots on said retainer flanges permitting lateral application of the blades onto said body so that each blade may be mounted with its tongues positioned in nonadjacent channels and then moved longitudinally to operating position on said body, retainer means on said body limiting longitudinal movement of said blades away from operating position, and spring means on each blade extending into one of said channels between those engaged by said tongues and acting to move the blade outward with respect to said body.

1l. In a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferentially, the ribs deiining a plurality of longitudinal channels therebetween, each of the ribs having a pair of longitudinally spaced grooves near one end thereof intersecting a side wall of an adjacent channel, a set of scraper blades mounted on said body, each blade having an arcuate outer face provided with teeth for engaging the inside surface of a casing, each blade having a retainer flange on each side edge thereof, each retainer flange having a tongue extending into one of said side channels, a central portion of one retainer flange on each blade having a slot, said grooves on said ribs and said slots on said retainer iianges permitting lateral application of the blades onto said body so that each blade may be mounted with its tongue positioned in said channels and then moved longitudinally to operating position on said body, and means for retaining said blades in operating position spaced from the location of said grooves.

12. In a casing scraper, the combination of: a body having a plurality of longitudinal ribs equally spaced circumferentially, the ribs deining a plurality of longitudinal channels therebetween, each of the ribs having a pair of longitudinally spaced grooves near one end thereof intersecting a side wall of an adjacent channel, trst and second sets of scraper blades mounted on said body, the rst set being circumferentially staggered with respect to the second set, each blade having an arcuate outer face provided with teeth for engaging the inside surface of a casing, each blade having a retainer ange on each side edge thereof, each retainer flange having an in-turned tongue extending into one of said side channels a central portion of one retainer flange on each blade having a slot, said grooves on said ribs and the slots on said retainer flanges permitting lateral application of the blades onto said body so that each blade may be mounted with its in-turned tongues positioned in nonadjacent channels and then moved longitudinally to an operating position on said body, retainer means on said body limiting longitudinal movement of said blades away from operating position, and spring means on each blade engaging one of said channels respectively and acting to move the blade outward with respect to said body.

Baker Feb. 2, 19'54 Guillot Oct. 29, 1957 

